Endoprosthesis of the proximal portion of the femur

ABSTRACT

An endoprosthesis of the proximal portion of the femur, wherein a head and a neck are connected with a shaft by means of a threaded joint. For this purpose the proximal end of the shaft has a broadening part, wherein a seat for a threaded split shank fitted on the neck base is provided about the length of the neck axis. The split shank is fixed by a lock for the trochanter major. Accordingly, the latter lock is elongated and broadens toward the end disposed inside the shaft.

United States Patent Shersher 5] Apr. 30, 1974 [54] ENDOPROSTHESIS OFTHE PROXIMAL 3,102,536 9/1963 Rose et al. 128/92 CA PORnON OF THE FEMURFOREIGN PATENTS OR APPLICATIONS [76] lnvemo" Isaevlch shershe" 12,015,324 11/1971 Germany 3/1 g y y pr z 3, W 124,585 0/1959 U.S.S.R128/92 c Saratov, U.S.'S.R. [22] Filed; Mar. 22, 1973 PrimaryExaminer-Richard A. Gaudet Assistant ExaminerRonald I. Frinks [21] Appl344032 Attorney, Agent, or Firm-Holman. & Stern [30] Foreign ApplicationPriority Data [57] ABSTRACT M 4, 1972 U.S.S.R 1776052 ay Anendoprosthesis of the proxImal port1on of the fe- 52 us. c1. 3/1 128/92CA wherein a head and a neck are connected with a 51 Int. Cl. A61f 1/24Shaft by means of a threaded For this PurP"Se Field of Search'm 3H. /9 C9 CA 2 R the proximal end Of the shaft has a broadening part, /92 9wherein a seat for a threaded split shank fitted on the I neck base isprovided about the length of the neck 56] References Cited axis. Thesplit shank is fixed by a lock for the trochanter major. Accordingly,the latter lock is elongated 2 8] 58 iz fi PATENTS 28/ 2 CA and broadenstoward the end disposed inside the shaft.

,7 ,7 eva ier 9 3064.645 11/1962 Ficat et al. 128/92 CA 1 Claim, 2Drawing Figures ENDOPROSTIIESIS OF THE PROXIMAL PORTION OF THE FEMUR Thepresent invention relates to artificial joints employed inintra-articular prosthetic replacement, and more particularly to anendoprosthesis of the proximal portion of the femur. Such anendoprosthesis may be employed both independently and as part of anartificial hip-joint to restore mobility in the hip-joint lost due toBekhterevs disease, arthritis deformans, arthritis infectiosa andaceptic necrosis of the femoral neck, as well as femoral neck fracturesin the aged.

Known in the art is to employ an endoprosthesis of the proximal portionof the femur, comprising a head passing into a neck and also containinga shaft with a lock for the trochanter major.

In the known endoprosthesis the head and neck are permanently connectedwith the shaft. Hence, if the head is worn out or the neck is fractured,the whole endoprosthesis including the shaft must be removed.

Besides, the mentioned endoprosthesis does not provide for varying theneck length depending on the individual anatomy of different patients.

It is an object of the present invention to provide an endoprosthesis ofthe proximal portion of the femur, wherein the head and neck would beconnected with the shaft by means of a detachable joint.

This object is accomplished by providing in an endoprosthesis of theproximal portion of the femur, comprising a head passing into a neck anda shaft wherein there is fixed a lock for the trochanter major, inwhich, in accordance with the present invention, the head and neck areconnected with the shaft by means of a threaded joint, for which purposethe proximal end of the shaft has a broadened part, wherein a seat isprovided about the axis of the neck to receive a threaded split shankfixed on the base of the neck, and the lock of the trochanter major iselongated and broadens toward the end thereof disposed inside the shaft,said lock simultaneously serving as a lock for the split shank of theneck.

The disclosed endoprosthesis of the proximal portion of the femur isadvantageous in the sense that the head can be replaced, if need be,without taking the shaft from the medullary canal, and also that theneck may be elongated or shortened depending on the specific anatomy ofdifferent patients.

An embodiment of the present invention will now be described, by way ofexample, with reference to the accompanying drawings, wherein:

FIG. 1 is a general view (with cut-away segments) of an endoprosthesisof the proximal portion of the femur, in accordance with the invention;

FIG. 2 is a view of asplit shank in FIG. 1 taken along the arrow A.

I The endoprosthesis of the proximal portion of the femur shown in FIG.1 comprises a head 1 passing into a neck 2 and a shaft 3 provided withfenestras 4 wherethrough burgeoning bony tissue can advance. Theproximal end of the shaft 3 has a broadened part 5, wherein a seat 7 isdrilled out along an axis 6 to receive a threaded split shank 8 fixed onthe base of the neck Besides, in the broadened part 5 of the shaft 3along an intertrochanteric axis 9 there is drilled out an orifice 10wherein there is disposed a lock for the trochanter major, the latterlock being formed as a screw 1 l, with one end thereof disposed insidethe boradened part 5 being elongated and broadened. The screw 11 and theshank 8 are so disposed relative to each other that the screw 11 passingthrough theslit of the shank 8 serves as a lock for the shank 8,preventing the neck 2 from self-unscrewing during the service of theprosthesis.

The screw 11 is locked by two nuts 12. Besides, the broadened part 5 hasan opening 13 provided for the convenience of the operating surgeon.

FIG. 2 is a view of the split shank 8 taken along the arrow A showingthe shape of the slit in the shank 8.

The proposed endoprosthesis of the proximal portion of the femur isassembled in the following manner.

The neck 2 is screwed into the seat 7 (FIG. 1). The screw 11 is led intothe orifice l0, narrow end first in such a way that it should passthrough the slit in the shank 8. After that the screw 11 is locked withtwo nuts 12, in which process the screw 11 is tightened and the shank 8is securely locked against self-unscrewing.

What is claimed is:

1. An endoprosthesis of the proximal portion of the femur, comprising ahead, said head extending into a neck having a base thereon, a shaftdesigned for being inserted into the femoral medullary canal, said shafthaving a proximal end defining a broadened part, a seat formed in saidbroadened part along the axis of said neck, a threaded split shank fixedon the base of said neck, a threaded joint connecting said neck withsaid shaft by screwing said split shank into said seat, a lock for thetrochanter major having one end disposed in said broadened part of saidshaft, said end of said lock for the trochanter major being elongatedand broadened for the purpose of locking said split shank.

1. An endoprosthesis of the proximal portion of the femur, comprising ahead, said head extending into a neck having a base thereon, a shaftdesigned for being inserted into the femoral medullary canal, said shafthaving a proximal end defining a broadened part, a seat formed in saidbroadened part along the axis of said neck, a threaded split shank fixedon the base of said neck, a threaded joint connecting said neck withsaid shaft by screwing said split shank into said seat, a lock for thetrochanter major having one end disposed in said broadened part of saidshaft, said end of said lock for the trochanter major being elongatedand broadened for the purpose of locking said split shank.